They also launched formal probes into 100 other politicians, businessmen and members of the secret service, including an ex-mayor of Rome and the “anti-corruption tsar”.

Prosecutors say gangsters in the capital have made hundreds of millions of euros by rigging contracts for rubbish collections and park maintenance, as well as embezzling cash intended to help refugees and migrants.

And ringleaders bragged the deals proved even more lucrative than the mob’s drug trade.

Dubbed the Mafia Capitale, the mob is independent of known mafias such as Cosa Nostra in Sicily or the Camorra in Naples.

But Rome’s chief prosecutor Giuseppe Pignatone said: “With this operation we have answered the question of whether the mafia exists in Rome. The answer is, it certainly does.”

And they claim wire-tap evidence, plus the £161million of assets seized from Carminati’s home, will prove he is The Godfather.

Born in 1958, Carminati joined La Banda della Magliana, the most feared gang in Rome in the 70s and 80s, and lost his left eye when he was shot while fleeing the police in 1981.

He got a 10-year prison term in 1998 for his involvement with their activities but was freed early and avoided further spells inside.

Carminati was also in neo-fascist terror group the Armed Revolutionary Nuclei – linked to some of Italy’s most brutal killings, including the assassination of Prime Minister Aldo Moro in 1978.

Assassination: The 56-year-old was linked to the death of former PM Aldo Moro

The group was behind the bombing of Bologna train station in 1980, which killed 85.

Carminati’s far-right terrorism inspired a character called Il Nero in TV series Romanzo Criminale, which aired here in 2011.

Seemingly untouchable, he grew ever bolder – building an empire that penetrated Rome’s political and administrative establishment.

His HQ was a nondescript petrol station on the outskirts of Rome, but he revelled in being called the Last King and considered himself an intellectual art collector.

When police raided his home they found works by Warhol and Jackson Pollock and confiscated items worth tens of millions of euros.

Carminati also has a home in Notting Hill, West London, and plans to buy more property in the UK. Other profits have been traced to the Bahamas, Switzerland and Venezuela, according to Rome’s Il Messaggero paper.

Carminati likened his empire to Lord of the Rings’ Middle Earth. He called it a shadowy realm where corrupt politicians met with hardened street criminals, with himself as arbitrator and facilitator. He said: “It’s like the living above, and the dead below.”

Growing arrogant, Carminati held mafia councils in a cafe frequented by lawyers and doctors in the rich Vigna Clara area. But he was secretly being recorded as police closed in.

Mordor: Carminati likened his empire to Middle-earth (Image: Caters)

In one tape, Carminati described how the mob would decide in the morning who would be killed that night. He said he was not involved in drug ­trafficking but bragged: “I used to rob 10 banks a month.”

In another tape he talked chillingly about his weapon of choice – praising the Russian semi-automatic Makarov pistol with a silencer. “You don’t even hear the clack,” he said. “Before anyone notices, the pool of blood is already spreading.”

Carminati could also call on his heavies, including a “thumb-breaker” called Watson the Elementary due to his limited intellectual prowess.

He boasted of contacts such as other mafia bosses, managers at the Bank of Italy and state-run arms conglomerate Finmeccanica, and ex-mayor Gianni Alemanno.

Investigators believe high-ranking officials in the mayor’s office were handed £10,000 bribes, often in envelopes stuffed with notes, to steer contracts their way.

Money meant for waste management, public garden maintenance and providing accommodation for immigrants and gypsies ended up in Carminati’s coffers, prosecutors claim.

And in a tapped call, his right-hand man, Salvatore Buzzi, was apparently heard boasting about their line of work.

Buzzi, 59, was jailed for murder in 1984 but now runs a social co-operative in a run-down part of Rome. It boasts of helping “the integration of members of the public belonging to the most vulnerable areas of society”.

But in the tape he bragged: “Do you have any idea how much I make on immigrants? Drug trafficking is less profitable. We closed this year with turnover of 40 million [euro]... our profits all came from the gypsies, on the housing emergency and on the immigrants.”

Tens of thousands of African migrants make the tough trip across the Mediterranean to Sicily and on through Italy and mainland Europe, hoping for a new life.

More than 150,000 have entered via the island this year alone – and mafia chiefs are cashing in on their misery.

The influx means dozens of hotels have been turned into immigrant centres, which get £23 per immigrant per day from the government. With some 30,000 migrants housed in Italy it is easy money for mafia “hoteliers”.

One Sicilian senator, Mario Michele Giarrusso, said recently: “The interest is to open as many as possible and keep the migrants there.

“The longer they keep them, the more money they bring in... it’s a business. Migrants die in the Strait of Sicily just to bring millions of euros to the mafia.”

The scale of the corruption and the exploitation of vulnerable refugees and Roma gypsies has been condemned.

Consumer rights group Federconsumatori called it a horrifying situation that goes “beyond the darkest hypothesis”.

It is not the first time Carminati has been linked to powerful political figures. In the 90s he was part of a high profile court case involving Italy’s most famous post-war leader, Giulio Andreotti.

The seven-times PM was sensationally charged with ordering the murder of Mino Pecorelli, a journalist threatening to reveal his darkest political secrets.

Murdered: Italian journalist Mino Pecorelli's body is seen sprawled across the front seat of his car

Mr Pecorelli was shot in the head twice in March 1979, allegedly by Carminati and a hitman hired by Cosa Nostra. But Andreotti, then 80, Carminati and four others were cleared after a trial.

Just days ago Carminati was arrested again on a rural road north of Rome. In the same sting officers searched the home and office of Mr Alemanno – an ally of former PM Silvio Berlusconi.

And a news agency reported a foundation of which the president got £30,000 from Carminati. But Mr Alemanno, 56, said: “I have nothing to do with this.”

In a further twist, it emerged Rome’s anti-corruption tsar, Italo Walter Politano, was also being investigated for suspected links to the Mafia Capitale. He was appointed by current Mayor Ignazio Marino, who claims to have “barricaded the door to murky deals”.

But earlier this year it was revealed there is a £16billion hole in Rome’s accounts, caused by decades of incompetence and corruption.

The “eternal city” was almost shut down until central government bailed it out – for the sixth year running.

So it is little wonder the Mafia Capitale revelations have caused a “political-judicial earthquake” there.

Carminati has not been charged with any offences but is being held in jail. Prosecutors believe they have the upper hand – but those who know him believe he may still have trump cards to play. There are rumours of his links to “elements of the forces of order and secret services”.